# SetHintValue Stores data needed during authorization as a key-value pair. ``` int (*)(struct __OpaqueAuthorizationEngine *, const char *, const struct AuthorizationValue *) SetHintValue; ``` ## Parameters `inEngine` An opaque handle that is passed to your plug-in when the authorization engine calls your [`MechanismCreate`](/documentation/Security/AuthorizationPluginInterface/MechanismCreate) function. `inKey` A key identifying the value you are storing. For standard values such as a time stamp, use the keys listed in `DirectoryService/DirServicesConst.h`. If you need to define a new key, make sure the key is unique. For example, you can use your company name as a prefix for the key name. `inValue` A pointer to an [`AuthorizationValue`](/documentation/Security/AuthorizationValue) structure that contains the size of the data and a pointer to the data. Both the structure and the data are copied to storage maintained by the authorization engine. ## Return Value A result code. Possible results are [`errAuthorizationSuccess`](/documentation/Security/errAuthorizationSuccess) (no error) and [`errAuthorizationInternal`](/documentation/Security/errAuthorizationInternal) (Security Server internal error). ## Discussion Your plug-in authorization mechanism can save and retrieve auxiliary information—called hints—for use by subsequent mechanisms that are part of the same authorization. You use the `SetHintValue` function to have the Security Server store this data and the [`GetHintValue`](/documentation/Security/AuthorizationCallbacks/GetHintValue) function to retrieve it. Hints are not preserved as part of the authorization result; once all mechanisms have approved the authorization or any mechanism has denied it, the security engine disposes of the hints. The authorization engine sends you the entry point to the `SetHintValue` function in an [`AuthorizationCallbacks`](/documentation/Security/AuthorizationCallbacks) structure when you call the [`AuthorizationPluginCreate`](/documentation/Security/AuthorizationPluginCreate) function. > Important: > Do not call this function after you have called the ``doc://com.apple.security/documentation/Security/AuthorizationCallbacks/SetResult`` function. If you do so, the function does not set the hint data, even though the function returns the ``doc://com.apple.security/documentation/Security/errAuthorizationSuccess`` result code. --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)